From: enselic@gmail.com
To: matthew.garrett@nebula.com, bleung@chromium.org, olof@lixom.net
Cc: miletus@chromium.org, platform-driver-x86@vger.kernel.org,
        linux-kernel@vger.kernel.org, Martin Nordholts <enselic@gmail.com>
Subject: [PATCH 0/1] Platform: x86: chromeos_laptop - convert to i2c_driver to handle i915 race
Date: Thu, 18 Jul 2013 17:58:10 +0200
Message-Id: <1374163091-4750-1-git-send-email-enselic@gmail.com>
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1825
Lines: 50

From: Martin Nordholts <enselic@gmail.com>

Hello,

I have looked into solving the "touchpad/touchscreen not working on
boot"-problem on Chromebook Pixel, see for example Brock Tice's last
comment on https://plus.google.com/+LinusTorvalds/posts/1iFsBWBqoYY

I have seen Olof's attempt at a fix:

  [PATCH] Platform: x86: chromeos_laptop: defer probing if no i2c busses found
  https://lkml.org/lkml/2013/4/18/556

At first, I tried Olofs suggestion at the end of the thread, namely to
do bus_register_notifier() on i2c_bus_type, but it is a bit awkward:
How do you know that the i2c_adapter you are notified about is ready
to be interacted with? While investigating this, I noticed that the
i2c_driver has a .detect() mechanism, which is exactly what we need: A
callback when a newly added i2c_adapter is initialized and ready to be
used.

Since all chromeos_laptop does is to instantiate i2c devices, I
figured it would be nice to simply convert chromeos_laptop into a
i2c_driver. The result is the patch in the next mail (based on
v3.11-rc1).

I have gone through the SubmitChecklist and done everything that
applied. I have however only tested this patch on the Chromebook
Pixel, as that is what I have. I will need help with verifying the
patch on other Chromebooks.

But first, what do you think about my patch?

/ Martin

Martin Nordholts (1):
  Platform: x86: chromeos_laptop - convert to i2c_driver to handle i915
    race

 drivers/platform/x86/chromeos_laptop.c |  426 +++++++++++++++-----------------
 1 file changed, 194 insertions(+), 232 deletions(-)

-- 
1.7.10.4

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